DESCRIPTION: (Applicant's Description) The applicants propose a prospective study to characterize the nature and severity of abstinence effects which occur during nicotine deprivation in a sample of adolescent smokers (age range 13-17). The study will be conducted in two stages. In Stage 1, the applicants will assess subjective (craving DSM-IV nicotine withdrawal symptoms) and objective abstinence effects (heart rate, blood pressure) in 200 adolescent smokers on three separate occasions over the course of an 8 hr. Period. In Stage 1, participants will be allowed to smoke cigarettes on an ad lib basis. In Stage 2, these same adolescent smokers will be randomized to wear a 15 mg nicotine patch (n=100) for 8 hrs and to refrain from smoking over this period. During this second 8 hr period, the applicants will again measure subjective and objective abstinence effects on three separate occasions. The specific aims of Stage 2 are as follows: (1) to measure subjective and objective abstinence effects during an 8 hour period of abstinence; (2) to study the effect of a transdermal nicotine patch in alleviating the development of subjective abstinence effects associated with an 8 hr period of abstinence. Three primary hypotheses will be examined in Stage 2: Hypothesis #1: Subjective abstinence effects that develop over an 8 hr period of nicotine deprivation will be significantly higher than subjective abstinence effects measured during 8 hrs of ad lib smoking. Hypothesis #2: Heart rate measured during an 8 hr period of nicotine deprivation will be significantly lower than heart rate measure during 8 hrs of ad lib smoking. Hypothesis #3: Adolescent smokers who refrain from smoking over an 8 hr period while wearing one placebo patch. If, through studies such as the one the applicants propose, it can be demonstrated that adolescent smokers experience significant abstinence effects associated with nicotine deprivation, increased attention may then be refocused on (a) how pharmacologic and biologic factors interact with social processes to influence smoking among children and adolescents; (b) how these factors may affect the transition from experimental to regular use, and (c) how to account for nicotine dependence in cessation treatments for adolescent smokers.